A number
of experiments were deployed and two impressive landmarks, Stone
Mountain and the North Ray crater, visited. Samples taken from
the rim of North Ray crater later proved to be bedrock thrown
up from the meteorite impact that had created it. Three moon walks
with lunar
surface activities totaling 20 hours and 17 minutes were accomplished
by Young and Duke. The crew remained on the lunar surface for
a total of about 71 hours. After lunar liftoff, the Lunar Module
rendezvoused with the Command Module and Mattingly.

When the
crew returned to orbit, tensions rose as it was discovered that
a faulty engine on Casper, the Command Module, had to fire. The
module was taken around the far side of the Moon where the burn
would take place as Mission Control waited for news.

The burn
had the desired effect as the astronauts re-established radio
contact, and entry and landing proceeded as normal.